Diaphragm spring clutch assembly

ABSTRACT

A friction clutch diaphragm spring having radially inwardly extending fingers at least one of which is deformed at its inner end so that the inner ends of the fingers can bear simultaneously on opposite sides of a groove in a thrust means to prevent vibration between the diaphragm spring and the thrust means and thus prevent rattling occurring at least when the clutch is in the engaged position.

United States Patent Inventor Peter F. Baker Benarth, Conway, WalesAppl. No. 820,496 Filed Apr. 30, 1969 Patented Mar. 16, 1971 AssigneeQuinton Hazell (Holdings) Limited North Wales, Great Britain PriorityMay 3, 1968 Great Britain 20999/68 DIAPHRAGM SPRING CLUTCH ASSEMBLY 12Claims, 10 Drawing Figs.

US. Cl l92/70.27, 192/89 Int. Cl F16d 13/50 Field of Search 192/7027,

[56] References Cited UNITED STATES PATENTS 1,644,548 10/1927 Spase192/70.27(X) 2,138,169 11/1938 Hunt 192/70.27 2,630,897 3/1953 Porterl92/89(B) 2,885,047 5/1959 Kehrl n 192/89(B)(X) 2,952,453 9/1960Haussermann..." 192/89(B)(X) 3,361,239 l/1968 Binder 192/89(B) PrimaryExaminer-Allan D. Herrmann Alt0rney Friedman & Goodman ABSTRACT: Afriction clutch diaphragm spring having radially inwardly extendingfingers at least one of which is deformed at its inner end-so that theinner ends of the fingers can bear simultaneously on opposite sides of agroove in a thrust means to prevent vibration between the diaphragmspring and the thrust means and thus prevent rattling occurring at leastwhen the clutch is in the engaged position.

DIAPHRAGM SPRING CLUTCH ASSEMBLY BRIEF SUMMARY OF THE INVENTIONAccording to the present invention there is provided a diaphragm springfor a friction clutch, the diaphragm spring having radially inwardlyextending fingers which, at their radially inner ends, form a radiallyinner portion defining a central aperture characterized in that theoverall width W" of the radially inner portion is wider axially than thethickness T of the material of which said spring is made so as to becapable of bearing simultaneously with spring pressure on opposite sidesof a groove in a thrust means to prevent relative vibration between thediaphragm spring and the thrust means at least when the clutch is in anengaged position.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will now be moreparticular described by way of example with reference to theaccompanying drawings in which:

FIG. 1 is a longitudinal sectional view of a friction clutch on linesindicated at II-II in FIG. 2 and shown in an engaged position and alsoshowing the diaphragm spring in dotted lines in a free position and in adisengaged position of the clutch;

FIG. 2 is a perspective view of the diaphragm spring in a free position;

FIG. 3 is a cross-sectional view of one form of diaphragm spring ofwhich the upper half is shown in a free position and of which the lowerhalf is shown in an engaged position of the clutch;

FIG. 4 is a similar view to FIG. 3 but showing another form of diaphragmspring;

FIG. 5 is a developed diagrammatic sectional edge view of a fragmentarypart of a unit comprising a part of a diaphragm spring and a thrustmeans with the clutch in an engaged position;

FIG. 6 is a fragmentary perspective view of a further form of diaphragmspring;

FIG. 7 is a fragmentary sectional view of the diaphragm spring shown inFIG. 6 in engagement with a thrust means;

FIG. 8 is a developed diagrammatic sectional edge view of a fragmentarypart of a unit similar to FIG. 5 but including the diaphragm spring asshown in FIGS. 6 and 7;

FIG. 9 is a developed diagrammatic sectional edge view of a fragmentarypart of a unit showing a still further form of diaphragm spring; and

FIG. 10 is a developed diagrammatic sectional edge view of a fragmentarypart of a unit showing a different form of thrust means.

DESCRIPTION OF THE PREFERRED EMBODIMENT For convenience similarreference numerals will be used through the several views to denotecorresponding parts.

The friction clutch illustrated in FIG. I is intended for a motor drivenroad vehicle and comprises a flywheel which forms the driving plate ofthe clutch as is well known and to the flywheel is bolted a cover 22 andmounted within the cover is a pressure plate 24 which rotates with theflywheel 20 and between the flywheel 20 and the pressure plate 24 isdisposed a driven friction plate 26 which is associated with a drivenshaft in any convenient manner not shown.

The clutch also comprises a unit including a diaphragm spring 2% and athrust means 30 which affords a face 32 capable of cooperating with aclutch release thrust device, not shown, which is movable parallel withthe axis A-A of the clutch by, for example, a clutch pedal in order tocontrol the clutch.

The diaphragm spring 28 comprises an outer imperforate rim from whichextends radially inwardly a plurality of, for example, l2 fingers 34although it should be appreciated that the diaphragm spring may beformed with any suitable number of fingers such as, for example, 18fingers. The fingers are separated by radial slots 36 which are formedwith enlarged openings at their radially outer ends to receive theshanks of headed pins 38 secured to the cover 22 and on which pins aresupported two fulcrum rings 40 which bear against the heads 42 of thepins and against the cover 22 and the diaphragm spring is disposedbetween the rings at a position between the radially inner and outeredges of said spring as shown in FIG.

The radially inner ends of the fingers 34 form a radially inner portion41 defining a central aperture 44 and said ends are located in acontinuous annular groove 46 formed in the thrust means 30 while theouter peripheral edge portion 48 of the diaphragm spring is associatedin any convenient manner, which is diagrammatically illustrated in FIG.I, with the pressure plate 24, so that when the thrust means 30 is movedtowards the left as shown in FIG. I the pressure plate 24 is movedtowards the right and vice versa in a known manner.

The thrust means 30 is made of nonresilient metal or plastics materialor any other suitable material and provides two opposite rigid shoulders50 and 52 which assist in defining the groove 46 and while saidshoulders are of curved crosssectional shape as shown in FIG. 7 they maybe of any other convenient cross-sectional shape.

As shown in FIGS. 1, 5, 7, 8 and 9 of the drawings each shoulder iscircumferentially smooth, i.e. is nonundulatory around anycircumferential circular path on the surface of the shoulder and aboutthe axis A-A, except for projections hereinafter referred to, so thateach shoulder is straight as viewed in side elevation of the thrustmeans as seen in FIGS. 5, 8 and 9.

Alternatively, however, one or both of the faces or shoulders of thethrust means 30 may be of castellated formation as indicated at 54 inFIG. 10.

Whether the shoulders are as shown in FIGS. 1, 5, 7, 8 and 9 or as shownin FIG. 10, the fingers bear with spring pressure at positions which, onthe respective shoulders, are in common planes as clearly shown in FIGS.5, 8, 9 and 10.

The diaphragm spring 28 is shown in FIG. I in full lines in the positionit occupies when the clutch is engaged and in this position thediaphragm spring is stressed and also in FIG. 1 the diaphragm spring isindicated in dotted lines at 23A in a free unstressed position as alsoshown in FIG. 2 and the upper halves of FIGS. 3 and 4, this being theposition and form the diaphragm spring assumes before assembly into theclutch. Also in FIG. I the diaphragm spring 28 is shown in dotted linesat 28B in the position the diaphragm spring assumes when the clutch isin the disengaged position and said spring is stressed further than whenthe clutch is in the engaged position.

The thrust means 30 comprises a nonresilient metal thrust member 54providing the face 32 and a nonresilient metal retaining member 56 whichincludes a sleeve 58 received within a bore 60 formed in the thrustmember 54 and an end wall of the sleeve 58 abuts an annular abutmentwall 60 of the thrust member 54 whereby the shoulder 50 is correctlypositioned in a fixed axially spaced apart relationship to the shoulder52 to form the groove 46.

The thrust means 30 comprising the thrust member 54 and the retainingmember 56 is applied to the diaphragm spring 28 before the two members54 and 56 are placed together and subsequently the two members aresecured together with the fingers 34 between the shoulders 50 and 52 bypressing radial projections 62 outwardly from the sleeve 58 to engage anannular groove or recess 64 in the bore 60 of the thrust member 54 andconveniently six such radial projections are provided and areequiangularly spaced apart. The engagement of the radial projections 62with the annular groove 64 may be relied upon to relatively position thetwo members 54 and 56 in correct angular relationship but additionallythese two members may be keyed together.

In order to prevent relative vibration and thus rattling occurringbetween the diaphragm spring 28 and the thrust means 30 at least whenthe clutch is in an engaged position the diaphragm spring is formed sothat the overall width of the radially inner portion of said spring iswider axially as indicated at W than the thickness T of the material ofwhich the spring is made so that said spring is capable of bearingsimultaneously with spring pressure on opposite sides of the groove 46in the thrust means 30 and which groove is wider than the thickness T,to prevent relative vibration between the diaphragm spring and thethrust means at least when the clutch is in an engaged position. Thus itis not necessary to employ a Bellville washer for the purpose ofpreventing vibration and rattling.

Referring to FIGS. 2, 3, 4 and 5, two fingers 34A are of normal straightformation in cross section along a radial axis BB whereas the thirdfinger 34B of each three fingers is bent as shown in FIG. 3 eithersharply or in a gradual curve about a bend line 66 adjacent the radiallyouter ends of the fingers or about a bend line 68 adjacent the radiallyinner ends of the fingers so that the radially inner end of the finger34B is wholly displaced relatively to the fingers 34A.

The relative set of the fingers 34A and 34B is such that the overallaxial width W of the radially inner portion of the diaphragm spring orfingers in the free unstressed position is greater than the width of thegroove 46 so that when the fingers are engaged with the groove 46 of thethrust means 30, the fingers bear simultaneously on the oppositeshoulders 50 and 52 and prevent relative vibration and rattling betweenthe diaphragm spring and the thrust means when the clutch is in a clutchengaged position but said fingers do not bear simultaneously on the twoshoulders 50 and 52 when the clutch is in the clutch disengagedposition.

It should be appreciated that there are preferably a plurality offingers 34A and a plurality of fingers 34B spaced at intervals aroundthe diaphragm spring so that a balanced engagement between the diaphragmspring and the thrust means is obtained around these two parts.

Instead of only the fingers 348 being bent, fingers 34C may also be bentbut in an axial direction opposite to the direction in which the fingers34B are bent as indicated in FIG. 3.

Referring to FIGS. 6, 7 and 8 the fingers 34 of the diaphragm spring 28are bent or twisted about the radial axis BB so that the two oppositesubstantially radial edges 70 and 72 are axially spaced apart so thatthe edge 70 bears against one shoulder of the groove 46 andsimultaneously the other edge 72 bears against the other shoulder ofsaid groove except when the clutch is in a clutch disengaged position.It should be appreciated that one or more but not necessarily all of thefingers 34 of a diaphragm spring need be twisted.

Referring to FIG. 9 a finger 34 is deformed so as to be of substantiallycurved channel-shape in cross section so that substantially radial edges76 of the finger are axially spaced from a central part or base 78 ofthe finger disposed circumferentially between said edges 76. Thus thesubstantially radial edges 76 bear against one shoulder of the groove 46and simultaneously the other part or base 78 of the finger bears againstthe other shoulder of the groove 46 except when the clutch is in aclutch disengaged position.

It should be appreciated that in the form of the diaphragm springillustrated in FIG. 9 one or more but not necessarily all of the fingersneed be deformed or bent into channel crosssectional formation.

Formed on the shoulder 52 of the thrust member 54 are axial projections,for example, four equiangularly spaced apart axial projections 80previously mentioned and which are positioned to engage the slots 36between adjacent fingers 34 so that the thrust means 30 and thediaphragm spring 28 rotate together but instead of providing said axialprojections 80 on the thrust member 54 said projections may be providedon the retaining member 56.

The invention thus provides a diaphragm spring which can engage a groovein a thrust means so that both shoulders of the annular groove aresimultaneously engaged by the diaphragm spring to prevent relativevibration between these two parts and thus prevent rattling occurringespecially when the clutch is in an engaged position and furthermoreprovides a unit for a friction clutch comprising such a diaphragm springand thrust means and provides a friction clutch assembly comprising sucha unit and a cover and a pressure plate and also provides a frictionclutch comprising such a friction clutch assembly and the unit, assemblyor friction clutch is more simple and less expensive than known frictionclutches of the kind specified.

lclaim:

l. A diaphragm spring for a friction clutch said diaphragm spring (28)having an outer imperforate rim and fingers (34) which extend radiallyinwardly therefrom and which, at their radially inner ends, form aradially inner portion (41) defining a central aperture (44) wherein theimprovement comprises at least one finger (34) being deformed so thatparts (70,72) or (76, 78) of the radially inner end of said one fingerare axially spaced apart a distance such that the overall width W' ofsaid one finger and thus said radially inner portion is wider axiallythan the thickness T" of the material of which the spring is made so asto be capable of bearing simultaneously with spring pressure on oppositesides (50, 52) of a groove (46) in a thrust means (30) to preventrelative vibration between the diaphragm spring and the thrust means atleast when the clutch is in an engaged position.

2. A diaphragm spring according to claim l wherein the improvementcomprises the said one finger 34) being deformed about a radial axisthereof so that substantially opposite radial edges (70,72) of said onefinger are axially spaced apart to afford the width W.

3. A diaphragm spring according to claim 1 wherein the improvementcomprises the said one finger (34) being deformed and of channel shapein cross section so that substantially radial edges (76) of said onefinger are axially spaced from a part (78) of said one finger disposedcircumferentially between said radial edges to afford the width W."

4. A unit for a friction clutch comprising a diaphragm spring (28)having an outer imperforate rim and fingers (34) which extend radiallyinwardly therefrom and which, at their radially inner ends, form aradially inner portion defining a central aperture (44) and a thrustmeans (30) which is disposed in said central aperture and is engaged bythe radially inner ends of said fingers wherein the improvementcomprises at least one finger (34) being deformed so that the overallwidth W of said radially inner portion is wider axially than thethickness T of the material of which said spring is made and acontinuous annular groove (46) is formed in the thrust means and affordstwo axially spaced apart rigid shoulders (50,52) which are spaced aparta fixed distance greater than the thickness T and said one finger atleast and the remaining fingers bear with spring pressure simultaneouslyon said rigid shoulders at positions which, on the respective shoulders,are in common planes, to prevent relative vibration between thediaphragm spring and the thrust means at least when the clutch is in anengaged position.

5. A unit for a friction clutch according to claim 4 wherein theimprovement comprises the said one finger (34) being deformed about aradial axis thereof so that substantially opposite radial edges (70,72)of said one finger are axially spaced apart to afford the width W,saidopposite radial edges bearing with spring pressure simultaneously on thespaced apart rigid shoulders (50,52) of the continuous groove at leastwhen the clutch is in an engaged position.

6. A unit for a friction clutch according to claim 4 wherein theimprovement comprises the said one finger (34) being deformed and ofchannel shape in cross section so that substantially radial edges (76)of said one finger are axially spaced from a part (78) of the fingerdisposed circumferentially between said radial edges to afford the widthW,"- said substantially radial edges (76) and the part (78) disposedcircumferentially therebetween bearing with spring pressuresimultaneously on the spaced apart rigid shoulders (50,52) of thecontinuous groove at least when the clutch is in an engaged position.

7. A friction clutch assembly wherein the improvement comprises a unitaccording to claim 4, a cover (22) supporting a fulcrum (40) for thediaphragm spring between the radially inner portion (41) and the outerimperforate rim of said spring and a pressure plate (24) with which saidouter imperforate rim of the spring cooperates to move said pressureplate axially.

8. A friction clutch assembly wherein the improvement comprises a unitaccording to claim 5, a cover (22) supporting a fulcrum (40) for thediaphragm spring between the radially inner portion (41) and the outerimperforate rim of said spring and a pressure plate (24) with which saidouter imperforate rim of the spring cooperates to move said pressureplate axially.

9. A friction clutch assembly wherein the improvement comprises a unitaccording to claim 6, a cover (22) supporting a fulcrum (40) for thediaphragm spring between the radially inner portion (41) and the outerimperforate rim of said spring and a pressure plate (24) with which saidouter imperforate rim of the spring cooperates to move said pressureplate axially.

10. A friction clutch wherein the improvement comprises a frictionclutch assembly according to claim 7, of which the cover (22) is securedto a driving plate (20) and a driven plate (26) is disposed between thedriving plate (20) and the pressure plate (24).

11. A friction clutch wherein the improvement comprises a frictionclutch assembly according to claim 8 of which the cover (22) is securedto a driving plate 20) and a driven plate (26) is disposed between thedriving plate (20) and the pressure plate (24).

12. A friction clutch wherein the improvement comprises a frictionclutch assembly according to claim 9 of which the cover (22) is securedto a driving plate (20) and a driven plate (26) is disposed between thedriving plate (20) and the pressure plate (24).

1. A diaphragm spring for a friction clutch said diaphragm spring (28)having an outer imperforate rim and fingers (34) which extend radiallyinwardly therefrom and which, at their radially inner ends, form aradially inner portion (41) defining a central aperture (44) wherein theimprovement comprises at least one finger (34) being deformed so thatparts (70,72) or (76, 78) of the radially inner end of said one fingerare axially spaced apart a distance such that the overall width''''W'''' of said one finger and thus said radially inner portion iswider axially than the thickness ''''T'''' of the material of which thespring is made so as to be capable of bearing simultaneously with springpressure on opposite sides (50, 52) of a groove (46) in a thrust means(30) to prevent relative vibration between the diaphragm spring and thethrust means at least when the clutch is in an engaged position.
 2. Adiaphragm spring according to claim 1 wherein the improvement comprisesthe said one finger (34) being deformed about a radial axis thereof sothat substantially opposite radial edges (70,72) of said one finger areaxially spaced apart to afford the width ''''W.''''
 3. A diaphragmspring according to claim 1 wherein the improvement comprises the saidone finger (34) being deformed and of channel shape in cross section sothat substantially radial edges (76) of said one finger are axiallyspaced from a part (78) of said one finger disposed circumferentiallybetween said radial edges to afford the width ''''W.''''
 4. A unit for afriction clutch comprising a diaphragm spring (28) having an outerimperforate rim and fingers (34) which extend radially inwardlytherefrom and which, at their radially inner ends, form a radially innerportion defining a central aperture (44) and a thrust means (30) whichis disposed in said central aperture and is engaged by the radiallyinner ends of said fingers wherein the improvement comprises at leastone finger (34) being deformed so that the overall width ''''W'''' ofsaid radially inner portion is wider axially than the thickness''''T'''' of the material of which said spring is made and a continuousannular groove (46) is formed in the thrust means and affords twoaxially spaced apart rigid shoulders (50,52) which are spaced apart afixed distance greater than the thickness ''''T'''' and said one fingerat least and the remaining fingers bear with spring pressuresimultaneously on said rigid shoulders at poSitions which, on therespective shoulders, are in common planes, to prevent relativevibration between the diaphragm spring and the thrust means at leastwhen the clutch is in an engaged position.
 5. A unit for a frictionclutch according to claim 4 wherein the improvement comprises the saidone finger (34) being deformed about a radial axis thereof so thatsubstantially opposite radial edges (70,72) of said one finger areaxially spaced apart to afford the width ''''W,'''' said opposite radialedges bearing with spring pressure simultaneously on the spaced apartrigid shoulders (50,52) of the continuous groove at least when theclutch is in an engaged position.
 6. A unit for a friction clutchaccording to claim 4 wherein the improvement comprises the said onefinger (34) being deformed and of channel shape in cross section so thatsubstantially radial edges (76) of said one finger are axially spacedfrom a part (78) of the finger disposed circumferentially between saidradial edges to afford the width ''''W,'''' said substantially radialedges (76) and the part (78) disposed circumferentially therebetweenbearing with spring pressure simultaneously on the spaced apart rigidshoulders (50,52) of the continuous groove at least when the clutch isin an engaged position.
 7. A friction clutch assembly wherein theimprovement comprises a unit according to claim 4, a cover (22)supporting a fulcrum (40) for the diaphragm spring between the radiallyinner portion (41) and the outer imperforate rim of said spring and apressure plate (24) with which said outer imperforate rim of the springcooperates to move said pressure plate axially.
 8. A friction clutchassembly wherein the improvement comprises a unit according to claim 5,a cover (22) supporting a fulcrum (40) for the diaphragm spring betweenthe radially inner portion (41) and the outer imperforate rim of saidspring and a pressure plate (24) with which said outer imperforate rimof the spring cooperates to move said pressure plate axially.
 9. Afriction clutch assembly wherein the improvement comprises a unitaccording to claim 6, a cover (22) supporting a fulcrum (40) for thediaphragm spring between the radially inner portion (41) and the outerimperforate rim of said spring and a pressure plate (24) with which saidouter imperforate rim of the spring cooperates to move said pressureplate axially.
 10. A friction clutch wherein the improvement comprises afriction clutch assembly according to claim 7, of which the cover (22)is secured to a driving plate (20) and a driven plate (26) is disposedbetween the driving plate (20) and the pressure plate (24).
 11. Afriction clutch wherein the improvement comprises a friction clutchassembly according to claim 8 of which the cover (22) is secured to adriving plate (20) and a driven plate (26) is disposed between thedriving plate (20) and the pressure plate (24).
 12. A friction clutchwherein the improvement comprises a friction clutch assembly accordingto claim 9 of which the cover (22) is secured to a driving plate (20)and a driven plate (26) is disposed between the driving plate (20) andthe pressure plate (24).